Combustion apparatus for a gas turbine

ABSTRACT

A gas turbine having a fuel nozzle which is encompassed by a plurality of annular plenum chambers which are supplied with pressurized fluid which is directed at an angle toward a fuel stream being sprayed into the combustion chamber from the fuel nozzle to atomize and disperse the fuel to promote more complete combustion and minimize smoke. A vent or a frustoconical baffle is also utilized to stabilize the combustion of the fuel during an ignition portion of the operating cycle of the turbine.

0 W11 States Patent 11 1 1111 3,768,250 Kawaguchi 1 51 Oct. 30, 1973 [54] COMBUSTION APPARATUS FOR A GAS 3,153,438 10/1964 Brzozowski 239/405 TURBINE 3,563,470 2 1971 Suzuki 60 39.?4 R Y 2,630,024 12/1971 Hopkins 60/39.74 R Inventor: Katsuyukl Kawaguchl, 3,684,186 8/1972 Helmrich 60/39.?4 R Japan 3,690,093 9/1972 Carlisle 60/3974 R [73] Assignee: Mitsubishi Jukogyo Kabushiki K i h T k Ja an Primary Examiner-Douglas Hart [22] Filed Dec 1 1971 Attorney-A. T. Stratton et a1.

[21] Appl. No.: 203,670 [57] ABSTRACT A gas turbine having a fuel nozzle which is encom- [52] 60/39'74 gg igg passed by a plurality of annular plenum chambers which are supplied with pressurized fluid which is dilg rected at an angle toward a fuel stream being sprayed 3 5 into the combustion chamber from the fuel nozzle to atomize and disperse the fuel to promote more complete combustion and minimize smoke. A vent or a [56] References Cited frustoconical baffle is also utilized to stabilize the UNITED STATES PATENTS combustion of the fuel during an ignition portion of 1,799,459 4/1931 Fantz 239/400 the operating cycle of the turbine. 2,595,759 5/1952 Buckland 60/39.74 R 2,762,656 9/1956 Frazer 60/39.74 R 6 Claims, 3 Drawing Figures PAIENIEnumo m 3.768250 SHEET 3 or 3 VENT COMBUSTION APPARATUS FOR A GAS TURBINE CROSS REFERENCES TO RELATED APPLICATIONS This invention is based on a series of Japanese applications flled by the inventor in Japan. The list of the Japanese application numbers and their filing dates is as follows:

124,798/70 filed Dec. 15, 1970 124,799/70 filed Dec. 15, 1970 30,43l/7l filed Apr. 21, 1971 30,432/71 filed Apr. 21, 1971 BACKGROUND OF THE INVENTION This invention relates to combustion apparatus for a gas turbine, and more particularly to means'for admixing fluid streams with the. fuel to atomize or disperse the fuel to provide for complete combustion thereof.

Early arrangements of baffling and admixing of atomizing fluids and fuel have generally been concerned with increasing the thermal combustion efficiency and optimizing the temperature distribution of the'products of combustion to eliminate hot spots and prevent'burnout of the components in the flow path of the products of combustion. However, with the increased interest in ecology, interest has been generated in providing admixing of the fuel and air to abate the production of smoke and obnoxious nitrogen oxygen compounds produced by the combustion of the fuel in the gas turbine.

SUMMARY OF THE INVENTION In general, a combustion apparatus for a gas turbine, when made in accordance with this invention, comprises a fuel supply conduit having a pore in fluid communication with a combustion chamber to direct the flow of fuel to the combustion chamber, an atomizing fluid chamber having an opening disposed to direct atomizing fluid to converge with the fluid flowing into the combustion chamber, an annular chamber disposed to encircle the fuel supply conduit and have one end thereof in communication with the combustion chamber and in communication with the compressor portion of the gas turbine, the annular chamber having a plurality of vanes so disposed therein to cause air flowing therethrough to follow a swirling path as it leaves the end of the annular chamber and enters the combustion chamber, and a high pressure fluid chamber in communication-with the supply of pressurized fluid at a pressure greater than the discharge pressure of the compressor. The high pressure fluid chamber has a plurality of ports disposed to cause pressurized fluid flowing through the ports to converge with the fuel entering the combustion chamber, and the atomizing and high pressure fluids cooperate to reduce the size of the fuel particles and to increase the dispersion of the fuel to reduce the smoke and nitrogen-oxygen compounds produced by the combustion, of the fuel.

BRIEF DESCRIPTION OF THE DRAWINGS The objects and advantages of this invention will become more apparent from reading the following detailed description in connectionwith the accompanying drawings, in which:

FIG. I is a vertical sectional view of a combustion apparatus for a gas turbine made in accordance with this invention;

FIG. 2 is a vertical sectional view of the combustion apparatus showing a modification;

FIG. 3 is a vertical sectional view of the combustion apparatus showing a further modification.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings in detail, FIG. 1 shows a combustion apparatus 1 for a gas turbine (not shown) having a combustion chamber 3, a fuel supply nozzle 5, a compressor (not shown) to supply pressurized air for combustion, and a supply conduit 7 to supply atomizing fluid to atomize the fuel.

A fuel supply conduit 9 delivers fuel to the fuel sup ply nozzle 5 which has at least one pore or opening from which fuel is sprayed into the combustion chamber 3.

An outer annular plenum chamber 11 encircles the combustion apparatus and is in communication with the compressor through a plurality of ports 13 disposed in a cylindrical outer wall 15 and has one end opening into the combustion chamber 3. A plurality of swirl vanes 17 are fastened to and extend radially outwardly from an inner cylindrical wall 19 of the plenum chamber 11. The swirl vanes 17 are adapted to cause the air flowing through the plenum chamber to follow a swirl ing path as it enters the combustion chamber. A frustoconical baffle 21 has its smaller diameter end fastened to the inner wall 19 of the plenum chamber 11 and has a plurality of ports or holes 22 so disposed therein to direct discrete jets of air at an angle toward the fuel flowing into the combustion chamber.

An inner annular plenum chamber 23 is formed adjacent the fuel nozzle 5 and is supplied with atomizing fluid through the atomizing fluid conduit 7. The atomizing fluid flows through an opening 27 adjacent the tip of the nozzle 5 and is directed at an angle toward the fuel flowing into the fuel chamber converging with the fuel flowing to the combustion chamber.

An intermediate annular plenum chamber 29 is formed between the inner and outer annular plenum chambers 23 and 11, respectively, and a plurality of ports 3l are disposed in the inner wall 19 of the outer plenum chamber 11 and the intermediate annular plenum chamber 29 is open adjacent the tip of the fuel nozzle 5 allowing air to flow therethrough to cool the fuel nozzle.

The discrete jets of air flowing through the ports 22 cooperate with the atomizing fluid reducing the size of the fuel particles, atomizingand dispersing the fuel to burn the fuel more completely and reduce smoke and obnoxious nitrogen-oxygen compounds, N0

The swirl vanes 17 have a baffle 33 which comprises an outer cylindrical ring portion 34 which encircles the swirl vanes and a frustoconical portion 35 which flares outwardly from the downstream edge of the ring portion 34. Air from the compressor flows between the ring portion 34 and the outer wall 15 of the annular plenum chamber 11 and between the frustoconical portion 35 and the wall of the combustion chamber 13 to provide a boundary layer of air along the wall of the combustion chamber to cool it.

Referring now to FIG. 2 the combustion apparatus 41 for a gas turbine is shown to have a combustion chamber 43, a compressor (not shown) for supplying pressurized air, a supply of atomizing fluid for atomizing the fuel in communication with an atomizing air conduit 44, and a supercharger 45 for supplying pressurized fluid at a pressure generally one to two atmospheres higher than the pressure of the air supplied by the compressor. While the supercharger 45 is shown the high pressure fluid need not be air as steam or other fluids may be utilized.

Fuel is supplied through a fuel nozzle 47 via a fuel supply conduit 49. The fuel nozzle 47 has at least one pore in communication with the combustion chamber 43 through which fuel is sprayed therein.

An annular inner plenum chamber 51 encircles the nozzle 47 and is in communication with the atomizing fluid conduit 44 through which the atomizing fluid is supplied thereto. The end of the plenum chamber 51 has an opening 53 in communication with the combustion chamber 43 and is so disposed that the atomizing fluid flowing therethrough is directed at an angle to the fuel flowing into the combustion chamber and converges therewith.

An intermediate annular plenum chamber 55 encircles the inner annular plenum chamber 51 and is in communication with a high pressure fluid conduit 57 which is in fluid communication with the supercharger 45. The intermediate annular plenum chamber 55 is also placed in communication with the combustion chamber by a plurality of ports 59, which direct the high pressure fluid at an angle to the ,stream of fuel flowing into the combustion chamber so that they converge therein.

The jets of high pressure fluid and the atomizing fluid cooperate to atomize and disperse the fuel to promote more complete combustion and reduce the production of the smoke and toxic nitrogen-oxygen compounds, NO

An outer annular plenum chamber 61 encircles the intermediate plenum chamber 55 and is in communication with the compressor through a plurality of ports 63 in an outer cylindrical wall 64 and has one end opening into the combustion chamber 43. A plurality of swirl vanes 65 are fastened to and extend radially outwardly from an inner cylindrical wall 67 separating the outer and intermediate chambers 61 and 55, respectively. The swirl vanes 65 taper outwardly as they extend radially and are adapted to cause the air passing thereby to enter the combustion chamber following a swirling path.

A frustoconical baffle 69 has its smaller diameter fastened to the combustion chamber end of the inner wall 67 and has a plurality of small ports 71 so disposed therein that they direct discrete jets of air at an angle toward the fuel stream flowing into the combustion chamber and converge therewith in the combustion chamber.

The atomizing fluid, the high pressure fluid and the discrete jets of air cooperate to atomize or reduce the size of the fuel particles and disperse the fuel particles to promote more complete combustion, and reduce smoke and toxic NO compounds. The frustoconical baffle 69 also advantageously helps stabilize ignition during the ignition portion of the operating cycle.

The combustion apparatus shown in FIG. 3 is generally the same as that shown in FIG. 2 except the frustoconical baffle 69 is omitted in FIG. 3 and a plurality of ports 73 placing the outer plenum chamber 61 in communication with the intermediate plenum chamber 55 are provided along with a vent conduit 75 in communication with the high pressure fluid conduit 57 and a solenoid valve 77 disposed in the high pressure fluid conduit 57 and a solenoid valve 79 disposed in the vent conduit 75. The valves 77 and 79 are so controlled and disposed that during the ignition portion of the cycle the valve 77 controlling the flow of high pressure fluid from the supercharger 45 is closed and the valve 79 controlling the vent line is open to allow compressed air to bleed from the outer plenum chamber 51 and improve the stability of combustion during the ignition portion of the cycle. The valves are also so controlled and disposed that during normal operation the valve 77 controlling the flow of fluid from the supercharger 45 is open and the valve 77 in the vent conduit 75 is closed providing more complete combustion of the fuel and a reduction of the smoke and NO compounds produced by combustion.

The arrangements hereinbefore described in FIGS. 1, 2 and 3 advantageously provide for more complete combustion of the fuel and reduce the smoke and NO, compounds during normal operation and provide ignition stability during the ignition portion of the cycle.

What is claimed is:

l. A combustion apparatus for a gas turbine having a combustion chamber, a fuel supply, a compressor to supply pressurized air for combustion, a supply of pressurized atomizing fluid to atomize the fuel and a supply of pressurized fluid supplied to said combustion apparatus at a higher pressure than that produced by said compressor, said combustion apparatus comprising a fuel supply nozzle having at least one port in communication with said combustion chamber and disposed to direct the flow of fuel to said combustion chamber,

an atomizing fluid chamber having at least one duct disposed to direct atomizing fluid into said combustion chamber so that it converges with the fuel flowing thereto,

a high pressure fluid chamber in fluid communication with said supply of pressurized fluid at a higher pressure than that produced by said compressor and having at least one port disposed to direct said high pressure fluid into said combustion chamber so that it converges with said fuel flowing thereto,

an arcuate chamber in communication with said compressor and said combustion chamber having means disposed therein for causing the air passing therethrough to follow a swirling path as it enters said combustion chamber, and said duct and port being cooperatively associated to direct said atomizing and high pressure fluid so that they admix with the fuel in such a manner as to reduce the size I of the fuel particles thereby stimulating more complete combustion and reducing the smoke produced by the combustion of said fuel.

2. A combustion apparatus as set forth in claim 1, wherein the high pressure fluid is generally at a pressure in excess of 1 atmosphere above that produced by the compressor.

3. A combustion apparatus as set forth in claim 1, wherein the atomizing chamber is an annular chamber encircling the fluid nozzle and has at least one duct so disposed to cause atomizing fluid to converge with the fuel flowing into the combustion chamber.

4. A combustion apparatus as set forth in claim 3, wherein the high pressure fluid chamber is an annular chamber so disposed to encircle the atomizing chamber and has a plurality of ports so disposed to cause high pressure fluid to enter the combustion chamber at an oblique angle with respect to the flow of fuel and to converge with the fuel flowing into the combustion chamber.

5. A combustion apparatus as set forth in'claim l, and further comprising a supply conduit in communication with the supply of high pressure fluid and the high pressure fluid chamber, control means disposed in said supply conduit to shut off said supply of high pressure fluid, a vent conduit in communication with said supply conduit and control means disposed in said vent conduit to shut off said vent conduit, means to operate said supply and vent conduit control means so that the supply conduit control means is open when the vent conduit control means is closed and an opening between the arcuate annular chamber and the high pressure annular chamber, said operating means being operable to open the vent conduit control means and close the supply conduit control means during an ignition portion of the operating cycle to improve ignition stability during this portion of the cycle and operable to close the vent conduit control means and open the supply conduit control means during the normal operation portion of the cycle to reduce smoke resulting from the combus tion of the fuel.

6. A combustion apparatus as set forth in claim 5, wherein the annular arcuate chamber has one end thereon opening into the combustion chamber and has a frustoconical baffle disposed with the smaller diameter end thereof attached to an inner wall of the annular arcuate chamber, said baffle having a plurality of small holes so disposed therein to cause discrete jets of air to be angled toward and'converge with the fuel flowing into the combustion chamber to provide for better dispersements of the fuel and reduce the smoke produced by the combustion of the fuels during normal operating periods and to increase the stability of the combustion during an ignition portion of the operating cycle. 

1. A combustion apparatus fOr a gas turbine having a combustion chamber, a fuel supply, a compressor to supply pressurized air for combustion, a supply of pressurized atomizing fluid to atomize the fuel and a supply of pressurized fluid supplied to said combustion apparatus at a higher pressure than that produced by said compressor, said combustion apparatus comprising a fuel supply nozzle having at least one port in communication with said combustion chamber and disposed to direct the flow of fuel to said combustion chamber, an atomizing fluid chamber having at least one duct disposed to direct atomizing fluid into said combustion chamber so that it converges with the fuel flowing thereto, a high pressure fluid chamber in fluid communication with said supply of pressurized fluid at a higher pressure than that produced by said compressor and having at least one port disposed to direct said high pressure fluid into said combustion chamber so that it converges with said fuel flowing thereto, an arcuate chamber in communication with said compressor and said combustion chamber having means disposed therein for causing the air passing therethrough to follow a swirling path as it enters said combustion chamber, and said duct and port being cooperatively associated to direct said atomizing and high pressure fluid so that they admix with the fuel in such a manner as to reduce the size of the fuel particles thereby stimulating more complete combustion and reducing the smoke produced by the combustion of said fuel.
 2. A combustion apparatus as set forth in claim 1, wherein the high pressure fluid is generally at a pressure in excess of 1 atmosphere above that produced by the compressor.
 3. A combustion apparatus as set forth in claim 1, wherein the atomizing chamber is an annular chamber encircling the fluid nozzle and has at least one duct so disposed to cause atomizing fluid to converge with the fuel flowing into the combustion chamber.
 4. A combustion apparatus as set forth in claim 3, wherein the high pressure fluid chamber is an annular chamber so disposed to encircle the atomizing chamber and has a plurality of ports so disposed to cause high pressure fluid to enter the combustion chamber at an oblique angle with respect to the flow of fuel and to converge with the fuel flowing into the combustion chamber.
 5. A combustion apparatus as set forth in claim 1, and further comprising a supply conduit in communication with the supply of high pressure fluid and the high pressure fluid chamber, control means disposed in said supply conduit to shut off said supply of high pressure fluid, a vent conduit in communication with said supply conduit and control means disposed in said vent conduit to shut off said vent conduit, means to operate said supply and vent conduit control means so that the supply conduit control means is open when the vent conduit control means is closed and an opening between the arcuate annular chamber and the high pressure annular chamber, said operating means being operable to open the vent conduit control means and close the supply conduit control means during an ignition portion of the operating cycle to improve ignition stability during this portion of the cycle and operable to close the vent conduit control means and open the supply conduit control means during the normal operation portion of the cycle to reduce smoke resulting from the combustion of the fuel.
 6. A combustion apparatus as set forth in claim 5, wherein the annular arcuate chamber has one end thereon opening into the combustion chamber and has a frustoconical baffle disposed with the smaller diameter end thereof attached to an inner wall of the annular arcuate chamber, said baffle having a plurality of small holes so disposed therein to cause discrete jets of air to be angled toward and converge with the fuel flowing into the combustion chamber to provide for better dispersements of the fuel and reduce the smoke produced by the combustion of the fuels during normal operating periods and tO increase the stability of the combustion during an ignition portion of the operating cycle. 